3-dimensional pump rotor profile

ABSTRACT

An example apparatus includes an outer rotor having a first axial face and a second axial face opposite the first axial face, wherein the first axial face comprises a circumferential contour defining a plurality of lobe faces, and wherein the second axial face comprises a transformed circumferential contour defining a corresponding plurality of lobe faces, where the transformed circumferential contour comprises at least one of a scale transformation of the circumferential contour or a rotational transformation of the circumferential contour; and an inner rotor configured to rotate eccentrically within the outer rotor, thereby forming a gerotor element for a fluid pump.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. provisional application63/184,554 filed on 5 May 2021, and entitled “WEDGE ROTOR AND DUAL WEDGEROTOR UNIQUE 3-DIMENSIONAL PUMP PROFILES” (BLUB-0001-P01).

The above application is incorporated by reference in the entirety forall purposes.

BACKGROUND

Presently known gerotor pumps have a number of challenges. Mostapplications of a gerotor pump have a strong preference for a fixedfootprint for the pump, for example applications where the pump isprovided as a replacement part, an aftermarket part, and/or a part thatis utilized over multiple model years (e.g., of a vehicle), wherecontinuity in the volumetric footprint of the pump is highly desirableto maintain continuity of the system design. However, within that fixedfootprint, there is often a need or desire to increase the throughput ofthe pump, for example to produce a system with a higher power ratingthat may require a greater flow rate burden for the pump.

Further, it is desirable to produce a pump that is capable to bemanufactured with standard machining equipment. For example, almost anydesign can be accommodated by a manufacturing technique such as a 3-Dprinting technique. However, 3-D printing in the present state of thetechnology greatly increases the manufacturing expense for many parts,and presently has limits in the final strength of the manufactured part.While it is desirable for a gerotor pump to be manufacturable withstandard machining equipment, aspects of the present disclosure arenevertheless beneficial even for a 3-D printed part, and 3-D printingtechnology will continue to improve in both increased capability andreduced cost. Accordingly, the benefits of the present disclosure areapplicable to both gerotor pumps manufactured using standard machiningoperations or 3-D printing operations.

SUMMARY

An example apparatus includes an outer rotor having a first axial faceand a second axial face opposite the first axial face, wherein the firstaxial face comprises a circumferential contour defining a plurality oflobe faces, and wherein the second axial face comprises a transformedcircumferential contour defining a corresponding plurality of lobefaces, where the transformed circumferential contour comprises at leastone of a scale transformation of the circumferential contour or arotational transformation of the circumferential contour; and an innerrotor configured to rotate eccentrically within the outer rotor, therebyforming a gerotor element for a fluid pump.

Certain further aspects of the example apparatus are describedfollowing, any one or more of which may be present in certainembodiments. An example transformation circumferential contour includesthe scale transformation, where the scale includes a value between 1.01to 1.10, between 1.01 to 1.30, and/or between 0.70 and 1.50, inclusive.An example transformation circumferential contour includes therotational transformation, where the rotation includes a value between1° and 10°, between 1° and 30°, and/or between 5° and 60°, inclusive.

An example method includes an operation to prepare an outer rotor havinga first axial face and a second axial face opposite the first axialface, where the first axial face includes a circumferential contourdefining a number of lobe faces, where the second axial face includes atransformed circumferential contour defining a corresponding number oflobe faces, and an operation to prepare an inner rotor configured torotate eccentrically within the outer rotor, thereby forming a gerotorelement for a fluid pump.

Certain further aspects of the example method are described following,any one or more of which may be present in certain embodiments. Anexample method includes preparing the outer rotor by machining an outerrotor blank in response to the transformed circumferential contour. Anexample method includes preparing the inner rotor by machining an innerrotor blank configured to rotate eccentrically within the outer rotor,thereby forming a gerotor element for a fluid pump. An example methodincludes performing the machining by applying a rotationaltransformation and/or a scale transformation of the circumferentialcontour. An example method includes preparing an outer rotor blankand/or an inner rotor blank each as a cast and/or a forged blank. Anexample method includes preparing the inner rotor with matching lobecontours to the outer rotor.

An example pump assembly includes an inner element and an outer element,where the inner element and outer element are configured to rotationallyengage thereby forming a number of dynamically changing pumping volumes,where at least one of the inner element or the outer element includes arotor (e.g., where the other one of the inner element or the outerelement includes a rotor or a stator), and where a major diameter of therotational engagement between the inner element and the outer elementincludes a Z-axis variability.

Certain further aspects of the example pump assembly are describedfollowing, any one or more of which may be present in certainembodiments. An example pump assembly includes the Z-axis variability asa rotational variability and/or a scaling variability. An example scalevariability includes a scale value between 1.01 to 1.10, between 1.01 to1.30, and/or between 0.70 and 1.50, inclusive. An example rotationalvariability includes a rotation value between 1° and 10°, between 1° and30°, and/or between 5° and 60°, inclusive.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram of a system including a gerotor pump.

FIG. 2 is a first axial face perspective view of an inner rotor and anouter rotor of a gerotor component.

FIG. 3 is a second axial face perspective view of an inner rotor and anouter rotor of a gerotor component.

FIG. 4 is a schematic cutaway view of a gerotor component.

FIG. 5 is a partial cutaway view of an outer rotor.

FIG. 6 is a top view of an outer rotor.

FIG. 7 is a perspective view of an outer rotor.

FIG. 8 is a top view of an outer rotor with a high rotationaltransformation.

FIG. 9 is a perspective view of an outer rotor with a high rotationaltransformation.

FIG. 10 is a schematic view depicting aspects of a scalingtransformation.

FIG. 11 is a schematic view depicting aspects of a scaling androtational transformation.

FIG. 12 is a schematic view depicting aspects of a scaling androtational transformation.

FIG. 13 is a schematic flow diagram of a procedure to manufacture agerotor component.

FIG. 14 is a schematic flow diagram of a procedure to prepare an outerrotor.

FIG. 15 is a schematic flow diagram of a procedure to prepare an outerrotor.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thedisclosure, reference will now be made to the embodiments illustrated inthe drawings and described in the following written specification. It isunderstood that no limitation to the scope of the disclosure is therebyintended. It is further understood that the present disclosure includesany alterations and modifications to the illustrated embodiments andincludes further applications of the principles disclosed herein aswould normally occur to one skilled in the art to which this disclosurepertains.

Throughout the present disclosure, an inner element of the gerotor pumpis referenced as an inner rotor, and an outer element of the gerotorpump is referenced as an outer rotor. It is possible to make a gerotorpump where the inner element is a stator, or where the outer element isa stator. Applications of the gerotor pump with the inner element orouter element as a stator are explicitly contemplated herein, but forclarity of the description, both elements will be referenced as a rotorherein.

The rotors herein are applicable to a gerotor pump, or an internal gearpump. Such pumps utilize an inner rotor having a number of teeth orlobes, interacting with matching recesses (formed by complementary teethor lobes on the outer rotor) on an outer rotor to dynamically formpressure chambers, and pressurize the fluid within. Generally, the outerrotor has one more recess (or tooth/lobe) than the inner rotor. Theinner rotor rotates on an eccentric axis relative to the outer rotor,sequentially forming the pressure chambers around the circumference ofthe outer rotor. The fluid may be expelled axially or radially,depending on the specific pump design and where fluid openings arearranged. The rotor designs herein are usable in a gerotor pump or aninternal gear pump according to any design, and the specifics of theoverall pump design are omitted to highlight the aspects of the presentdisclosure.

The available fluid volume deliverable by a gerotor pump is constrainedby the individual chamber volumes formed by the pump as the rotorsrotate relative to each other, and the rotational speed available forthe pump. The rotational speed of the pump is limited by the strength ofparts, the speed limits and/or power limits of the driving motor for thepump, and the dynamic pressure capability of the pump as the fluidresponds to high pump velocities, ultimately limited due to cavitation,fluid viscosity response to high shear, or the like. Further, rotationalspeeds may be limited due to NVH (noise, vibration, and harshness)constraints for the system—for example limiting sound volumes and/orsound frequencies due to operator acceptability limits. Accordingly,previously known systems are generally limited to increasing the pumpsize, and consequently the pump footprint, to increase the volumetricflow rate capability of the pump.

In addition to a high value on footprint consistency, many applicationsare constrained in overall size of components thereon, including fluidpumps. For example, automotive and aerospace applications have limitedspace for components, and significant limitation on weight requirementsfor components. Accordingly, many applications have a strong incentiveto minimize the size and/or weight of components, and/or hard limits onthe maximum size and/or weight of components. Accordingly, manyapplications have significant pressure to increase the performancecapability of components within a given weight and/or volume, and/or toincrease the specific performance of components per unit of weightand/or volume.

Aspects of the present disclosure greatly improve the volumetric flowcapability of the pump, primarily by increasing the maximum intakevolume of each dynamically formed chamber of the pump. Further, aspectsof the present disclosure increase the volumetric efficiency of thepump, by providing increased chamber shaping control that can limit themaximum dynamic pressures in the chamber, and conform the lobes andrecesses of the inner and outer rotors. Improvements to the volumetricefficiency result in increases to the effective fluid volume delivery,and lower pumping losses for a given fluid delivery performance

Embodiments of the present disclosure are set forth in the context of afluid operated on by the pump—for example with the pump pressurizing thefluid, and driven by an external power source such as an electric motor,mechanical coupling, or the like, and/or with the pump powering anotherdevice, accepting pressurized fluid and powering a shaft or othercoupling to a load. A fluid, as utilized herein, should be understoodbroadly, and includes at least any liquid, gas, colloid or colloidalsuspension, fluids having suspended or entrained solids, emulsion, orthe like.

Referencing FIG. 1, an example system 100 including a gerotor pump isschematically depicted. The example system 100 includes the pump 104,for example a housing that contains the gerotor 106 (e.g., the inner andouter rotor), ports for fluid inlet and outlet, or the like. In theexample, fluid intake 116 delivers fluid to the pump 104, and fluidexhaust 118 delivers pressurized fluid to the target 112. The pump 104may be any type of gerotor and/or internal gear pump as known in theart, with the aspects of the rotors as set forth herein. The system 100includes a drive 108 coupled to the rotor(s) to drive one or both of therotors, for example using a shaft 110 to couple the drive to therotor(s). The example of FIG. 1 includes a fluid reservoir 102, withrecycled fluid 114 from the load (target 112), for example in ahydraulic system, power steering system, certain fuel systems, or thelike. The example of FIG. 1 is non-limiting, for example the fluid maybe provided to a target 112 without recycling to the pump, dependingupon the application. Additionally or alternatively, the fluid reservoirmay instead be an intake stream, either unrelated to a fluid reservoir,or with a fluid reservoir that is positioned outside the system. Theexample of FIG. 1 depicts an illustrative context for the gerotor 106,but is not limiting to the present disclosure.

The example of FIG. 1 is described in the context of the pump 104operating as a pump, and receiving power from a drive 108. The aspectsof the present disclosure are equally applicable to the pump 104 actingas a power generator, for example driving a load (e.g., logicallypositioned at the location of the drive 108), and utilizing workingfluid pressure to power the load. Any such embodiments are explicitlycontemplated herein.

Referencing FIG. 2, an example gerotor component 200 is depicted, havingan inner rotor 216, an outer rotor 202, and an engagement collar 402allowing the pump to mechanically engage an external drive or load. Theengagement collar 402 is a non-limiting example, with externalengagement features formed on the rotor directly (e.g., reference FIG.3), or through any other arrangement. In the example of FIG. 2, an axialface 204 of the outer rotor 202 is depicted, and which is bounded by acircumferential contour 206 defining a number of lobes (e.g., atlocation 208) or recesses (e.g., at location 206) that interact withlobes and recesses of the inner rotor 216 to sequentially form fluidchambers, pressurizing the fluid to be expelled as a pressurized fluid,and/or accepting pressure from the fluid to provide mechanical energy toa load (e.g., expelling the fluid at a lower pressure than at theinlet). The housing of the gerotor utilizing the gerotor component 200includes ports arranged at appropriate locations to provide fluid inletand outlet functions, as is known in the art. In the example of FIG. 2,the inner rotor 216 includes lobes 210 and recesses 212 that interactwith the outer rotor 202 lobes and recesses, with tip engagement of eachrotor interacting to seal the sequentially formed chambers and supportpumping operations. In the example of FIG. 2, the inner rotor 216includes one less lobe than the outer rotor 202 (e.g., 9 lobes on theinner rotor versus 10 lobes on the outer rotor, in the example), wherethe inner rotor 216 rotates on an eccentric axis relative to the outerrotor, which is an arrangement generally understood for gerotors and/orinternal gear pumps.

Referencing FIG. 3, an example gerotor component 200 is depicted, whichis consistent with aspects of the embodiment of FIG. 2, viewed from theopposite axial face 304 of the outer rotor 202 relative to the axialface 214 visible in the example of FIG. 2. To illustrate somevariability that may be present in certain embodiments, the embodimentof FIG. 2 is depicted with an engagement collar 402, and the embodimentof FIG. 3 is depicted without an engagement collar 402. In the exampleof FIG. 3, the circumferential contour 306 of the second axial face 304is scaled relative to the axial face 204 on the other side of the outerrotor 202. The scaling of the axial face 304 results in a thinner outerwall for the outer rotor 202, but in combination with the thicker wallon the first side of the outer rotor 202 and the progressing wallthickness of the outer rotor 202 in the Z direction (e.g., a centerlineaxis perpendicular to the axial face) nevertheless provides forsufficient mechanical integrity of the gerotor component 200. Theexample scaling of the second axial face 304 relative to the first axialface 204 provides for a greater fluid volume in each chamber, as well asa higher compression ratio capability (e.g., depending upon thepositioning of the fluid inlet and outlet ports) for the pump due to thegreater difference between minimum and maximum volumes of each chamber.

The example of FIGS. 2 and 3 includes a conforming configuration of thelobes and recesses of the inner rotor, for example matching the scalingtransformation between the axial faces 204, 304 of the outer rotor. Incertain embodiments, a rotational transformation may be applied,additionally or alternatively, to the axial faces 204, 304, which wouldalso be matched by the inner rotor configuration. The inner rotorgeometry match to the outer rotor is an operational match, for examplewith an arrangement to provide the selected chamber geometry, sealingcapability, and the like, with other slight differences due to thedistinct number of lobes on each rotor. The example of FIG. 3 includeslobes 310 of the inner rotor defined on the axial face 314 of the innerrotor, and engaging recesses 306 of the outer rotor. Accordingly, thedescription herein stating that the inner rotor matches the outer rotor,that the inner rotor is configured to form a gerotor element for a fluidpump, or the like, indicates that the inner rotor is configured withsufficient matching to the outer rotor to perform the selected pumpingoperations. The modifications to the inner rotor relative to theconfiguration of the outer rotor is well understood to one of skill inthe art having the benefit of the present disclosure, and are notfurther set forth herein. In certain embodiments, the shape of thecontour lines 206, 306 may form a trochoid, and/or a modified trochoid,as will be understood by one of skill in the art.

Referencing FIG. 4, an example partial cutaway view of a gerotorcomponent 200 is depicted. The example cutaway view shows the outerrotor 202, the inner rotor 216, and the engagement collar 402. Thecontact positions between the rotors 202, 216 provide sealing for thefluid chambers, with gap areas (e.g., on the right side between therotors 202, 216) acting as the fluid chambers. The example of FIG. 4depicts an illustrative Z-axis 404 notation, showing an example Zdirection for the gerotor component 200. For example, Z-axis variabilityof the major diameter (or effective diameter, maximum diameter, and/orbase circle) of the inner rotor and/or the outer rotor in the Z-axisindicates that the cross section of the rotor varies in the Z-axis 404direction, for example in response to the scaling transformation and/orthe rotational transformation.

Referencing FIG. 5, an example partial cutaway view of an outer rotor202 is depicted. The example outer rotor 202 depicts a portion of theaxial face 204, with circumferential contour lines 502, 504 definingeach corresponding axial face of the outer rotor 202. The outer rotor202 thereby forms a number of lobes 506, which are the geometricalvolume formed between the lobe faces of each of the axial faces of theouter rotor 202. The lobe 506 in the example expands in the Z direction(going down, in the example of FIG. 5), due to the scaling ofcircumferential contour line 502 relative to circumferential contourline 504, and consequent changes in the axial faces on each side of theouter rotor 202.

Referencing FIG. 6, an example outer rotor 202 is depicted, having asecond circumferential contour line 504 that is both scaled and rotatedrelative to circumferential contour line 502. The scaling may beutilized to increase the chamber volumes and/or volume ratios, whilemaintaining sufficient mechanical integrity of the rotor 202. Therotation may be utilized to adjust the chamber volumes—for example byincreasing the volume of a given chamber (e.g., adding a diagonal aspectto the lobe 506 and resulting chamber(s)), providing for enhancedutilization of gerotor geometric footprint for fluid retention, and/oradjusting the mechanical stress profile of the rotor 202 (e.g., due tovarying wall thickness of the outer rotor, utilization of the lobes 506as a part of the supporting structure, e.g., as ribs providing someradial stress support, or the like). Additionally or alternatively, therotation may be utilized to enhance sealing, for example providing for agreater sealing surface area, a better matching of rotor edges forsealing, changes to the orientation of the seal, and/or a surface formachining operations to enhance sealing of fluid chambers duringoperations of the pump. In certain embodiments, the utilization of arotational transformation allows for reduced leakage from fluid chambersduring operations of the pump, including a reduction of leakage toeffectively zero leakage. Accordingly, the utilization of a rotationaltransformation also enhances volumetric efficiency of operating pump.Referencing FIG. 7, an example outer rotor 202 is depicted in aperspective view. The example of FIG. 7 is consistent with the exampleof FIG. 6.

Referencing FIG. 8, an example outer rotor 202 is depicted in a topview, where the example outer rotor 202 includes a high rotationaltransformation angle. The example of FIG. 8 is not limiting, and notnecessarily depicted according to scale, but nominally depicts arotational transformation of about 60°. The actual angle of therotational angle may be defined or determined in any manner, for exampledetermined according to a rotational difference between a feature of thefirst axial face 502 and a corresponding feature of the second axialface 504—for example a lobe face position, recess position, or the like.The rotational transformation angle, where present, may be any valueavailable according to the geometry of the outer rotor 202 (e.g., theZ-axis thickness of the rotor, the diameter of the rotor, and/or theradial thickness of the rotor), the desired purpose of the rotation(e.g., chamber volume control, mechanical stress control, and/orvolumetric efficiency control), or the like. It will be seen that higherangles may introduce design complexity, increase manufacturingdifficulty, and/or may not be possible depending upon the rotor size,number of lobes, etc. Embodiments herein may be varied from a 0°rotation (e.g., no rotational transformation applied) to about 60°rotation. In certain embodiments, even greater rotational transformationangles may be utilized, including up to about 70° rotation, 80°rotation, or 90° rotation. Referencing FIG. 9, an example outer rotor202 having a high rotational transformation angle is depicted in aperspective view, consistent with the example of FIG. 8. The example ofFIGS. 8 and 9 further include a scaling transformation. A given gerotorcomponent may be formed with an outer rotor having a scalingtransformation, a rotational transformation, or both.

Referencing FIG. 10, an example outer rotor 202 is depictedschematically in a partially transparent view. The example outer rotor202 includes a scaling transformation, for example where thecircumferential contour 502 for a first axial face is scaled relative tothe circumferential contour 504 for the second axial face. The scalingin the example may be normalized according to the smaller contour, forexample where the scaling factor is normalized to be a value equal to orgreater than one (1). The scaling available for a given outer rotor 202depends upon a number of factors, including at least: the desiredchamber volume(s) and/or volume ratios; the Z-axis thickness of therotor; the radial thickness of the rotor (e.g., including the resultingvariations thereof due to the scaling transformation); the diameter ofthe rotor; and/or the chamber volume and/or geometry encompassed by thechambers (e.g., based upon the stresses and/or forces present atoperating pressures). In certain embodiments, a scaling factor ofbetween about 1.0 (e.g., where no scaling transformation is applied) toabout 1.10 provides for significant flexibility in the pump capability,and encompasses numerous benefits of the present disclosure. The scalingfactor may be any value, such as up to about 1.30, up to about 1.50, orthe like. The scaling factor may be limited at the high end by certainconsiderations, such as manufacturability of the design, complicationsin sealing between the inner rotor and the outer rotor, diminishingreturns in chamber volume enhancement, minimum wall thickness of theouter rotor at the scaled axial face (e.g., the axial face correspondingto circumferential contour 504, in the example of FIG. 10), or the like.The limit of the scaling factor for a particular design, whether anengineering limit or a commercial value limit, will depend on thecharacteristics of the particular system, and will be readilydeterminable to one of skill in the art having the benefit of thepresent disclosure. The scaling factor, as utilized herein, referencesthe ratio between the diameters of corresponding aspects of thecircumferential contour lines 502, 504, for example at a lobe position,recess position, or the like. In certain embodiments, the scaling factormay be related to another aspect, such as the encompassed area within agiven contour, or other similar geometric parameters. Any suchconceptions of the scaling factor are contemplated herein, and therecited scaling factors would be adjusted accordingly (e.g., a diameterbased scaling factor of 1.2 may equate to an area-based scaling factorof 1.44, depending upon the specific geometry of the rotor and contourline(s)). In certain embodiments, including for certain applications,materials for the outer rotor, low pressure applications, or the like, ahigh scaling factor such as 1.70, 2.0, or higher, may be utilized. Theexample scaling factors set forth herein may be utilized in a broadrange of applications, including varying rotor materials, rotorgeometries, fluid compositions, pressure ratings, or the like.

Referencing FIG. 11, an example outer rotor 202 is depictedschematically in a partially transparent view. The example outer rotor202 includes a scaling transformation, for example where thecircumferential contour 502 for a first axial face is scaled relative tothe circumferential contour 504 for the second axial face, and arotational transformation, for example where the circumferential contour502 is rotated relative to the circumferential contour 504. The exampleof FIG. 11 depicts a rotational angle 1102 to illustrate the rotationpresent in the example, which is depicted at about 10 degrees ofrotation in the un-scaled illustration of FIG. 11. Referencing FIG. 12,an example outer rotor 202 is depicted, again with both a rotational andscaling transformation, and with a rotational angle 1102 of about 8degrees in the un-scaled illustration of FIG. 12. The examples of FIGS.11 and 12 are illustrative to depict certain aspects of the disclosure,and to provide a context for depicting scaling and rotation as set forthherein, but are not limiting to the available range of transformationsconsistent with embodiments of the present disclosure.

Referencing FIG. 13, an example procedure 1300 for manufacturing agerotor element, for example an inner rotor and an outer rotor to beutilized in a gerotor pump, is schematically depicted. The exampleprocedure 1300 includes an operation 1302 to prepare an outer rotorhaving a first axial face and a second axial face opposite the firstaxial face, where each axial face includes a circumferential contourdefining lobe faces thereon, and where the second axial face includes atransformed circumferential contour relative to the circumferentialcontour of the first axial face. The transformed circumferential contourmay be a scaling transformation and/or a rotational transformation, asset forth throughout the present disclosure. The example procedure 1300further includes an operation 1304 to prepare a complementary innerrotor to form, in combination with the outer rotor, a gerotor element(or gerotor component). In certain embodiments, a complementary innerrotor includes a geometry, lobe arrangement, and the like, such that theinner rotor may be utilized with the outer rotor in a gerotor pumpand/or inner gear pump. Any aspects of the inner rotor as set forththroughout the present disclosure are applicable to the procedure 1300and operation 1304.

Referencing FIG. 14, an example operation 1302 to prepare the outerrotor includes an operation to machine an outer rotor blank to at leastpartially apply the transformation. The outer rotor blank, whereapplicable, may be any type of precursor to the outer rotor, wheremachining operations are applied to form the final geometry of therotor. For example, the blank may be a billet or other simple geometrycomponent having sufficient material and geometry to define the outerrotor, where machining operations remove material to complete theformation of the outer rotor. In certain embodiments, the blank may be acast component, a near net component, or the like. In certainembodiments, the blank may be cast, forged, a sintered substrate, or thelike. Embodiments herein utilizing rotational and/or scaledtransformations are manufacturable with ordinary machining operations,as such embodiments provide tool accessibility and line-of-sightconsistent with ordinary machining capability. Example machiningoperations capable of producing rotors herein include, withoutlimitation, drilling, grinding, milling, lathing, or the like. Incertain embodiments, a 3-axis machine may be utilized, but for evencomplex configurations herein, a machine having 6-axis capability willbe generally sufficient for machining operations without extensivehandling, arranging, or the like with the workpiece.

Referencing FIG. 15, an example operation 1302 to prepare the outerrotor includes an operation to apply a scaling transformation and/or arotational transformation to the workpiece to generate the outer rotor.The application of the scaling and/or rotational transformations may beperformed, in part, by the preparation of the blank, and/or may beapplied completely or in part by machining operations. The exampleoperations of FIGS. 14 and 15, including the utilization of a blank andsubsequent machining, are equally applicable to the inner rotor. Thecapability to form the rotors utilizing ordinary machining operations ofmoderate complexity provides for a number of benefits, includingreduction in manufacturing cost, ready confirmation that the part hasbeen manufactured properly, and the like. In certain embodiments,additive manufacturing may be utilized to create a rotor and/or a blank(e.g., an additively manufactured near net component), which willnevertheless incorporate numerous other benefits of the presentdisclosure, and such manufacturing operations are contemplated herein.

An example manufacturing operation includes forming the outer rotorand/or the inner rotor with an extended contact lip, for example at theposition of the rotor(s) where contact is made to seal the fluidchambers. The extended contact lip(s) may be formed in the blank, wherepresent, and/or in the rotor(s) after machining operations. In theexample, a grinding or other removal operation may be utilized, toremove a designed amount of material from the lip, providing for asingle operation that is readily verifiable and repeatable to ensurethat the seal is a high quality seal. Based upon experience and testing,such operations to finalize the rotor seals provide for improved finalsealing, enhancing the volumetric efficiency of the final gerotorcomponent. Further, the extended lip and grinding operation has beenfound to further improve sealing in cooperation with rotationallytransformed embodiments, further improving the seal integrity. Furtherstill, the extended lip and grinding operation has been found to furtherimprove sealing when utilized with a sintered blank, allowing for asimple closely tolerance tip for sealing. Embodiments herein may utilizea fixed mold for the rotors, with excess length on each side for thelip, which is then ground to finalize the seal. Such operations providefor a highly manufacturable component with high performance for fluidvolume throughput and/or volumetric efficiency.

Certain logical groupings of operations herein, for example methods orprocedures of the current disclosure, are provided to illustrate aspectsof the present disclosure. Operations described herein are schematicallydescribed and/or depicted, and operations may be combined, divided,re-ordered, added, or removed in a manner consistent with the disclosureherein. It is understood that the context of an operational descriptionmay require an ordering for one or more operations, and/or an order forone or more operations may be explicitly disclosed, but the order ofoperations should be understood broadly, where any equivalent groupingof operations to provide an equivalent outcome of operations isspecifically contemplated herein. For example, if a value is used in oneoperational step, the determining of the value may be required beforethat operational step in certain contexts (e.g., where the time delay ofdata for an operation to achieve a certain effect is important), but maynot be required before that operation step in other contexts (e.g. whereusage of the value from a previous execution cycle of the operationswould be sufficient for those purposes). Accordingly, in certainembodiments an order of operations and grouping of operations asdescribed is explicitly contemplated herein, and in certain embodimentsre-ordering, subdivision, and/or different grouping of operations isexplicitly contemplated herein.

While the disclosure has been disclosed in connection with certainembodiments shown and described in detail, various modifications andimprovements thereon will become readily apparent to those skilled inthe art. Accordingly, the spirit and scope of the present disclosure isnot to be limited by the foregoing examples but is to be understood inthe broadest sense allowable by law.

What is claimed is:
 1. An apparatus comprising: an outer rotor having afirst axial face and a second axial face opposite the first axial face,wherein the first axial face comprises a circumferential contourdefining a plurality of lobe faces, and wherein the second axial facecomprises a transformed circumferential contour defining a correspondingplurality of lobe faces; wherein the transformed circumferential contourcomprises at least one of a scale transformation of the circumferentialcontour or a rotational transformation of the circumferential contour;and an inner rotor configured to rotate eccentrically within the outerrotor, thereby forming a gerotor element for a fluid pump.
 2. Theapparatus of claim 1, wherein the transformation circumferential contourcomprises the scale transformation, wherein the scale comprises a valuebetween 1.01 to 1.10, inclusive.
 3. The apparatus of claim 1, whereinthe transformation circumferential contour comprises the scaletransformation, wherein the scale comprises a value between 1.01 to1.30, inclusive.
 4. The apparatus of claim 1, wherein the transformationcircumferential contour comprises the scale transformation, wherein thescale comprises a value between 0.70 to 1.50, inclusive.
 5. Theapparatus of claim 1, wherein the transformation circumferential contourcomprises the rotational transformation, wherein the rotation comprisesa value between 1° and 10°, inclusive.
 6. The apparatus of claim 1,wherein the transformation circumferential contour comprises therotational transformation, wherein the rotation comprises a valuebetween 1° and 30°, inclusive.
 7. The apparatus of claim 1, wherein thetransformation circumferential contour comprises the rotationaltransformation, wherein the rotation comprises a value between 5° and60°, inclusive.
 8. A method, comprising: preparing an outer rotor havinga first axial face and a second axial face opposite the first axialface, wherein the first axial face comprises a circumferential contourdefining a plurality of lobe faces, and wherein the second axial facecomprises a transformed circumferential contour defining a correspondingplurality of lobe faces; preparing an inner rotor configured to rotateeccentrically within the outer rotor, thereby forming a gerotor elementfor a fluid pump.
 9. The method of claim 8, wherein the preparing theouter rotor comprises machining an outer rotor blank in response to thetransformed circumferential contour.
 10. The method of claim 9, whereinthe machining comprises applying a scale transformation of thecircumferential contour.
 11. The method of claim 9, wherein themachining comprises applying a rotational transformation of thecircumferential contour.
 12. The method of claim 9, wherein themachining comprises applying both a rotational transformation and arotational transformation of the circumferential contour.
 13. The methodof claim 9, further comprising preparing the outer rotor blank as one ofa cast or forged blank.
 14. The method of claim 9, wherein preparing theinner rotor comprises preparing the inner rotor with matching lobecontours to the outer rotor.
 15. A pump assembly, comprising: an innerelement and an outer element, wherein the inner element and outerelement are configured to rotationally engage thereby forming aplurality of dynamically changing pumping volumes; wherein at least oneof the inner element or the outer element comprises a rotor; and whereina major diameter of the rotational engagement between the inner elementand the outer element comprises a Z-axis variability.
 16. The pumpassembly of claim 15, wherein the Z-axis variability comprises arotational variability.
 17. The pump assembly of claim 16, wherein therotational variability comprises a rotation value between 1° and 60°,inclusive.
 18. The pump assembly of claim 15, wherein the Z-axisvariability comprises a scaling variability.
 19. The pump assembly ofclaim 18, wherein the scaling variability comprises a scaling valuebetween 1.01 and 1.50, inclusive.
 20. The pump assembly of claim 15,wherein the Z-axis variability comprises a rotational variability and ascaling variability.